1. Field of the Invention
The present invention relates generally to portable generators and methods for producing portable generators, and more particularly, but not by way of limitation, to an improved portable generator for providing a 120 volt (V) alternating current (AC) output and a direct current output (14V, 28V or 42 V) and methods of producing, installing and using such an improved alternator.
2. Brief Description of the Prior Art
There are many instances where it is helpful to have access to a portable generator having an Alternating Current (AC) output. For example, during emergencies when commercial AC power is knocked out by a natural disaster, such as a tornado or an earthquake, a need exists for a source of AC electricity to temporarily power various home appliances, such as a television, a refrigerator, a freezer, a lighting system, and a heating/cooling system to notify the homeowner of various weather conditions, prevent spoilage of food and/or inconvenience to the homeowner.
Moreover, people are frequently in locations where it is inconvenient or impossible to. run commercial AC electricity. For example, farmers or homeowners frequently use electrically powered tools to work on fences, trim bushes and trees and the like where it is inconvenient to run an extension cord to the site where the farmer or homeowner is working. During recreational activities, such as picnics, fishing, camping, and the like, people are frequently without a source of commercial AC electricity.
Many sources of electricity already exist. For example, alternators for vehicles are well known in the art. The prior art alternators, such as the CS-130 alternator manufactured by General Motors, generate three-phase AC electricity and convert the three-phase AC electricity to Direct Current (DC) electricity to meet the vehicle""s electrical needs. DC Outputs, such as cigarette lighter sockets, battery terminals and the like are provided with the vehicle so that the driver has a source of DC electricity.
Inverters, which connect to the DC outputs on the vehicle, exist. The prior art inverters convert the DC output from the vehicle into AC electricity. While it is true that the prior art inverters can provide a portable source of AC electricity, various drawbacks to the prior art inverters exist. For example, the prior art inverters are relatively inefficient because the prior art inverters connect to the DC output of the vehicle. This causes the three-phase AC electricity produced by the alternator to be converted from AC electricity to DC electricity by the alternator rectifier, and then converted from DC electricity to AC electricity by the inverter. Thus, the inverters do not provide enough AC electricity to adequately power many electrical appliances because of the losses and inefficiencies caused by the AC to DC and DC to AC conversions. Moreover, the prior art inverters are typically expensive and capable of operating while the vehicle is not running thereby discharging the vehicle""s battery. Discharging the vehicle""s battery makes it difficult for the battery to start the engine; reduces the life of the battery and causes inconvenience to the consumer. Moreover, most inverters in the market cannot supply AC power clear enough for precise equipment.
AC generators constructed for installation in commercial vehicles, such as large trucks and vans also exist. For example, one such AC generator is disclosed in U.S. Pat. No. 5,734,217. These AC generators provide an Alternating Current output, but no Direct Current output. The AC generator does not replace the alternator in the commercial vehicle. Rather, the AC generator is installed in addition to the alternator in the commercial vehicle. Thus, the vehicle has the alternator for producing DC electricity for the vehicle, and the AC generator for producing the AC electricity. This is expensive and not practical for vehicles typically owned by individual consumers, such as passenger vehicles. In fact, most passenger vehicles do not have enough space under the vehicle""s hood for the additional AC, generator.
Portable AC generators also exist. These portable AC generators are typically powered by a relatively small gasoline engine having a size of about 4 to about 5 horsepower. To Applicant""s knowledge, these AC generators do not provide a DC power output. These gasoline AC generators include both the generator and the, engine. These gasoline AC generators are inconvenient to move and to store because of their large physical size.
In light of the foregoing, there is a need for a portable generator providing both an AC output and a DC output, which is convenient for the consumer to use and cost-effective. It is to such an improved portable generator that the present invention is directed.
Broadly, the present invention relates to a portable generator assembly having a DC output port and an AC output port. The portable generator assembly is provided with an alternator, and a power converter.
The alternator is installable in a vehicle. The alternator is provided with a housing, a rotor coil, a plurality of stator windings, a voltage regulator, a rectifier, and an AC output port. The housing defines an alternator interior space. The rotor coil is disposed in the alternator interior space and is rotatably supported by the housing. The rotor coil generates a magnetic field. The plurality of stator windings is supported by the housing and positioned in the magnetic field for generating an AC output signal, typically having a voltage between about 9.5 VAC and 12 VAC for a 14V DC output, or between about 25 V AC to about 36 VAC for a 42V DC output. The voltage regulator is electrically connected to the rotor coil for controlling the intensity of the magnetic field.
The rectifier has an input and an output. The input of the rectifier is electrically connected to the stator windings such that the input of the rectifier receives the AC output signal generated by the stator windings. The rectifier converts the AC output signal to a DC output signal.
The AC output port is electrically connected to the stator windings for receiving the AC output signal, and thereby providing access to the AC output signal such that the AC output signal can provide AC power at a location outside of the housing.
The power converter is typically positioned outside of the housing of the alternator. The power converter is provided with a transformer, a frequency changer, and one or more than one electrical outlet. By way of example, the electrical outlet(s) is preferably a Ground Fault Circuit Interrupter (GFCI) electrical outlet. The transformer receives the AC output signal from the AC output port and increases the voltage of the AC output signal to at least about 120 V. The frequency changer receives the AC output signal having the increased voltage, and converts the variable frequency of the AC output signal (typically between about 160 Hz to about 800 Hz) to a substantially constant preset frequency of either 60 Hz or 50 Hz. The electrical outlet receives the AC output signal having the increased voltage and converted frequency such that upon plugging an electrical implement into the electrical outlet, AC electrical power is provided to the electrical implement.
Thus it can be seen that there are many advantages of the present invention. The portable generator assembly can be used for providing emergency AC electricity for temporarily powering one or more various home appliances, such as a television, a refrigerator, a freezer, a lighting system, and a heating/cooling system during emergencies. AC electricity can also be supplied at locations where commercial AC electrical power is not available by driving the vehicle having the alternator to the remote location.
Moreover, passenger vehicles having predetermined alternator spaces for receiving the alternator are widely available. The alternator of the present invention can be installed in these passenger vehicles without any costly modifications to the passenger vehicle. Thus, the present invention provides an economical alternative to the portable AC generators having the small gasoline engine.
In one preferred embodiment, the power converter is provided with a portable housing containing the transformer, the frequency changer and the electrical outlet. Assuming that the vehicle is an automobile, the power converter having the portable housing can be stored in the vehicle""s trunk when the power converter is not in use. In another preferred embodiment, the power converter is permanently installed in the vehicle so as to provide the vehicle with a permanent AC electrical outlet.
Other advantages and features of the present invention will become apparent to those skilled in the art when the following detailed description is read in conjunction with the attached drawings and appended claims.